Synthesis and biological evaluation of phenyl-1H-1,2,3-triazole derivatives as anti-inflammatory agents.

Rapid and efficient synthesis of a phenyl-1H-1,2,3-triazole library enabled cost-effective biological testing of a range of novel non-steroidal anti-inflammatory drugs with potential for improved drug efficacy and toxicity profiles. Anti-inflammatory activities of the phenyl-1H-1,2,3-triazole analogs synthesized in this report were assessed using the xylene-induced ear edema model in mice. At least four analogs, 2a, 2b, 2c, and 4a, showed more potent effects than the reference anti-inflammatory drug diclofenac at the same dose of 25 mg/kg. To explore relationships between the structural properties of phenyl-1H-1,2,3-triazole analogs and their anti-inflammatory activities in xylene-induced ear edema, comparative molecular field analysis was performed, and pharmacophores showing good anti-inflammatory activities were identified based on an analysis of contour maps obtained from comparative molecular field analysis. The anti-inflammatory effect on the molecular level was tested by the expression of tumor necrosis factor-alpha induced COX-2 using Western blots. Because the addition of the analog 2c caused the expression change of TNF-α induced COX-2, the molecular binding mode between 2c and COX-2 was elucidated using in silico docking.

Polyphenols bearing cinnamaldehyde scaffold showing cell growth inhibitory effects on the cisplatin-resistant A2780/Cis ovarian cancer cells.

Ovarian carcinoma remains the most lethal among gynecological cancers. Chemoresistance is a clinical problem that severely limits treatment success. To identify potent anticancer agents against the cisplatin-resistant human ovarian cancer cell line A2780/Cis, 26 polyphenols bearing a cinnamaldehyde scaffold were synthesized. Structural differences in their inhibitory effect on clonogenicity of A2780/Cis cells were elucidated using comparative molecular field analysis and comparative molecular similarity indices analysis. Structural conditions required for increased inhibitory activity can be derived based on the analysis of their contour maps. The two most active compounds (16 and 19) were selected and further characterized their biological activities. We found that compounds 16 and 19 trigger cell cycle arrest at the G2/M phase and apoptotic cell death in cisplatin-resistant A2780/Cis human ovarian cancer cells. The molecular mechanism of compound 16 was elucidated using in vitro aurora A kinase assay, and the binding mode between the compound 16 and aurora A kinase was interpreted using in silico docking experiments. The findings obtained here may help us develop novel plant-derived polyphenols used for potent chemotherapeutic agents. In conclusion, compounds 16 and 19 could be used as promising lead compounds for the development of novel anticancer therapies in the treatment of cisplatin-resistant ovarian cancers.

Design, synthesis and inhibitory activities of naringenin derivatives on human colon cancer cells.

Based on the previous result, several naringenin derivatives modified at position 7 with bulky substituents were designed and synthesized, and their inhibitory effects on HCT116 human colon cancer cells were tested using a clonogenic assay. The half maximal inhibitory concentrations (IC(50)) of five naringenin derivatives ranged between 1.20 µM and 20.01 µM which are much better than naringenin used as a control. In addition, new structural modification at C-4 of flavanone results in improving both the anti-cancer effect and anti-oxidative effect. In vitro cyclin dependent kinase 2 (CDK2) binding assay was carried out based on the previous results. To elucidate the possible interaction between naringenin derivatives and CDK2, in silico docking study was performed. This result demonstrates the rationale for the different inhibitory activities of the naringenin derivatives. These findings could be used for designing cancer therapeutic or preventive flavanone-derived agents.

1H and 13C NMR spectral assignments of 2'-hydroxychalcones.

Chalcones are of interest to medicinal chemists because their structures can be easily modified with various functional groups. The syntheses and biological activities of chalcones from natural sources are well known. In this study, 24 2'-hydroxychalcones bearing methoxy substituents were synthesized, among which five are new. The NMR data for all synthesized chalcones are described for the first time. The complete assignments of the (1)H and (13)C NMR data can be used for the identification of newly discovered and widely isolated, synthesized chalcones.

Isolation, structure elucidation, and biological evaluation of 16,23-epoxycucurbitacin constituents from Eleaocarpus chinensis.

Eight new 16,23-epoxycucurbitacin derivatives, designated as elaeocarpucins A-H (1-8), and five known cucurbitacins (9-13) were isolated from the chloroform-soluble partitions of separate methanol extracts of the fruits and stem bark of Elaeocarpus chinensis collected in Vietnam. Isolation work was facilitated using a LC/MS dereplication procedure, and bioassay-guided fractionation was monitored using HT-29 human cancer cells. The structures of compounds 1-8 were determined on the basis of spectroscopic data interpretation, with the absolute configurations of isomers 1 and 2 established by the Mosher ester method. Compounds 1-13 were evaluated in vitro against the HT-29 cell line and using a mitochondrial transmembrane potential assay. Elaeocarpucin C (3), produced by partial synthesis from 16α,23α-epoxy-3ß,20ß-dihydroxy-10αH,23ßH-cucurbit-5,24-dien-11-one (13), was found to be inactive when evaluated in an in vivo hollow fiber assay using three different cancer cell types (dose range 0.5-10 mg/kg/day, i.p.).

A compound isolated from Schisandra chinensis induces apoptosis.

Schizandra chinensis has been known to have five predominant tastes: salty, sweet, sour, astringent, and bitter. It has also been shown to have various effects on the cardiovascular system, gastrointestinal system, anti-inflammatory, central nervous system, endocrine system, and stress protect. However, its anti-cancer activity on colon carcinoma HCT-116 cells has not been yet been examined. Thus, in this study, we attempted to isolate a compound from Schisandra chinensis that induced apoptosis in HCT-116 cells. An active compound was found and identified to be Gomisin A. It displayed apoptotic activity through caspase-7 cleavage in colon carcinoma HCT-116 cells. In addition, we further assessed the effects of this compound using long-term survival clonogenic assay with HCT116 cells.

Relationship between the structures of flavonoids and their NF-κB-dependent transcriptional activities.

It has been previously shown that some flavonoids inhibit NF-κB; however, the structure-activity relationships between chalcone, flavanone, flavone, and isoflavone derivatives and their TNFα induced NF-κB inhibitory effects on HCT116 human colon cancer cells have not yet been reported. Therefore, in this study, the effects of flavonoid structure on inhibition of NF-κB were investigated. Based on the combined results of this study, the structure of the flavonoids was shown to affect NF-κB activation.

Antitumor activity of deoxypodophyllotoxin isolated from Anthriscus sylvestris: Induction of G2/M cell cycle arrest and caspase-dependent apoptosis.

An active compound having antitumor activity was isolated from the root of Anthriscus sylvestris. Structural studies revealed that it was deoxypodophyllotoxin (DPPT), and its biological activity was evaluated in HeLa human cervix carcinoma cells. Flow cytometric analysis showed that DPPT arrests the cell cycle in the G2/M phase prior to apoptosis. The mechanisms of action of DPPT involve inhibition of tubulin polymerization, dysregulation of cyclin A and cyclin B1 expression, and activation of caspases-3 and -7.

Identification of compounds exhibiting inhibitory activity toward the Pseudomonas tolaasii toxin tolaasin I using in silico docking calculations, NMR binding assays, and in vitro hemolytic activity assays.

Using in silico docking calculations, NMR analysis of target-ligand binding, and hemolytic activity assays, we searched a 30,000-compound library for an effective inhibitor of tolaasin I, a Pseudomonas tolaasii toxin that causes virulent infection in mushrooms. Of more than 30,000 compounds screened in silico, two compounds were selected. One of these compounds, sorbitololeic acid, bound to tolaasin I and inhibited its hemolytic activity in vitro. Therefore, sorbitololeic acid can be a potential inhibitor of tolaasin I.

NF-kappaB Activation by compounds found in Platycodon grandiflorum extract.

Compounds extracted from Platycodon grandiflorum were evaluated for an activation effect on nuclear factor-kappa B (NF-kappaB). In its active state, NF-kappaB turns on the expression of genes related to cell proliferation or death. NF-kappaB activators promote growth of neuron cells and can be used to control neurodegenerative diseases. The biological activity of P. grandiflorum extracts toward NF-kappaB had not yet been studied. Although the biological activity of several compounds extracted from P. grandiflorum was evaluated, only three exhibited any significant activation effect on NF-kappaB.

Inhibitory effect against Akt of cyclic dipeptides isolated from Bacillus sp.

Among thirteen strains of the genus Bacillus isolated from Shrimp-jeotkal in our laboratory, a strain BA34 showing good antifungal activity against Phytophthora infestans in a previous experiment was tested for the inhibitory effect against Akt, protein kinase B. Since Akt is known to play an important role in controlling apoptosis, its inhibitors can be used as potential apoptosis-inducing agents in the treatment of cancer. Two active compounds were isolated and their structures were determined. They have similar structures, despite showing different inhibitory effects. In order to elucidate the reasons for these different effects, three-dimensional studies were carried out.

Benzoflavonoids Structure Hinders Human Colon Cancer Clonogenicity.

BACKGROUND: Since flavonoids fused by benzene have been known for their potent chemopreventive effects, in this study, we examined the relationship between the structures and activities of benzoflavones, benzoflavanones, benzochalcones, and benzochalcone derivatives bearing the pyrazole moiety against human colon cancer cells. METHODS: We investigated the effect of 34 benzoflavonoids on the inhibition of colon cancer cells based on the clonogenicity. The biological activity values used for the quantitative structure-activity relationship (QSAR) calculations were obtained from the cell growth inhibition on the basis of clonogenicity. 3D-QSAR calculations were performed using comparative molecular field analyses (CoMFA) and comparative molecular similarity index analyses (CoMSIA). RESULTS: Of several CoMFA and CoMSIA models, the best models showing the highest cross validated correlation coefficient were selected and validated. The cell growth inhibition values were calculated using the above models. The structural conditions to show good cell growth inhibitory effects on human colon cancer cells were analyzed by CoMFA and CoMSIA contour maps. The contribution of steric fields remarkably decreased without any change in the contribution of the electrostatic field, which means that electrostatic contribution is more crucial than the steric contribution in the modification of benzoflavonoids. Furthermore, the increase in the hydrogen bond donor contribution was approximately proportional to the decrease in steric field contribution. CONCLUSION: This study demonstrated that benzoflavonoids structure hinders colon cancer clonogenicity. Most of the benzoflavonoids structures comprised a C-3 linkage between the naphthalene and phenyl moieties, which contained diverse functional moieties such as oxygen-fused rings, double bonds, pyrazole rings, and sulfur constituents, and were able to exhibit great potential in diverse anticancer effects. Also, the positions of the hydroxyl group close to the naphthalene and phenyl rings were crucial for activity against colon cancer. The structural conditions obtained here may help us design potent benzoflavonoids against colon cancer cells and predict their activities.

Inhibition of PDGF-induced migration and TNF-α-induced ICAM-1 expression by maltotetraose from bamboo stem extract (BSE) in mouse vascular smooth muscle cells.

SCOPE: Expression of intercellular adhesion molecule-1 (ICAM-1) on vascular smooth muscle cells (VSMCs) plays an important role in the progression of atherosclerosis. We investigated the effects of bamboo stem extract (BSE) on motility and ICAM-1 expression by using mouse MOVAS-1 cells. Active constituents of BSE exhibiting an inhibitory activity on TNF-α-induced ICAM1 expression were identified using HPLC. METHODS AND RESULTS: The effects of BSE on platelet-derived growth factor (PDGF)-BB-induced migration, tumor necrosis factor alpha (TNF-α)-induced expression of ICAM-1, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation were investigated. BSE inhibited migration of MOVAS-1 cells and sprout formation by mouse aorta explants. Reverse transcription PCR analysis and promoter reporter assays revealed that BSE suppressed ICAM-1 expression by inhibiting NF-κB activity. In addition, BSE reduced adhesion between VSMCs and monocytes. Several oligosaccharides were identified in BSE. Among the oligosaccharides contained in BSE, maltotetraose and stachyose were potent inhibitors of TNF-α-induced ICAM-1 expression. We confirmed that maltotetraose reduced PDGF-induced sprout formation by mouse aorta explants and inhibited TNF-α-induced NF-κB activation and ICAM-1 expression in MOVAS-1 cells. CONCLUSION: The BSE constituent maltotetraose may be beneficial in the suppression of early atherosclerosis development and could be developed as a dietary supplement for cardiovascular health.

Plant-derived flavones as inhibitors of aurora B kinase and their quantitative structure-activity relationships.

Although several plant-derived flavones inhibit aurora B kinase (aurB), quantitative relationships between the structural properties of plant-derived flavones and their inhibitory effects on aurB remain unclear. In this report, these quantitative structure-activity relationships were obtained. For quercetagetin, found in the Eriocaulon species, showing the best IC50 value among the flavone derivatives tested in this report, further biological tests were performed using cell-based assays, including Western blot analysis, flow cytometry, and immunofluorescence microscopy. In vitro cellular experiments demonstrated that quercetagetin inhibits aurB. The molecular-binding mode between quercetagetin and aurB was elucidated using in silico docking. Quercetagetin binds to aurB, aurA, and aurC and prevents the active phosphorylation of all three aurora kinases. In addition, quercetagetin triggers mitotic arrest and caspase-mediated apoptosis. These observations suggest that quercetagetin is an aurora kinase inhibitor. Induction of mitosis-associated tumor cell death by quercetagetin is a promising strategy for developing novel chemotherapeutic anticancer agents.

Assay development for the discovery of semaphorin 3B inducing agents from natural product sources.

Semaphorins are a class of membrane-bound and secreted proteins. They have been found to regulate basic cell functions such as axonal growth cone guidance and recent studies have focused on their effect on tumor progression. Semaphorin 3B (Sema3B) particularly is a secreted protein that has been known to modulate proliferation and apoptosis, processes that are critical for tumor progression and development. In spite of its importance, there is yet no high-throughput screening assay available to detect or quantify the expression of Sema3B for natural product anticancer drug discovery purposes. Therefore, the development of a new high-throughput bioassay for the discovery of Sema3B inducing agents from natural product sources is described herein. A wide variety of pure compounds and extracts from plants and microorganisms has been found suitable for screening using this Sema3B assay to detect and quantify the effect of Sema3B inducing agents and thereby identify new selective bioactive Sema3B lead compounds for anticancer drug discovery and development. Also, this new bioassay procedure is based on a high-throughput platform using an enzyme-linked immunosorbent assay that involves the optimization of sensitivity and selectivity levels as well as accuracy, reproducibility, robustness, and cost effectiveness.

Dichamanetin inhibits cancer cell growth by affecting ROS-related signaling components through mitochondrial-mediated apoptosis.

BACKGROUND/AIM: Dichamanetin is a C-benzylated flavanone isolated as a major secondary metabolite from Piper sarmentosum, a plant used as a spice in Southeast Asia. This study aimed to investigate the path through which dichamanetin exerts its antiproliferative effect. MATERIALS AND METHODS: The study of several signaling cellular components, namely, reactive oxygen species (ROS) levels, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcription factor, mitochondrial membrane potential, DNA binding, poly ADP-ribose polymerase (PARP1) inhibition and proteasome inhibition was performed using an enzyme-linked immunosorbent (ELISA) assay, cell sorting, and western blot. RESULTS: Dichamanetin significantly reduced the cell viability of various types of human cancer cells (HT-29 colon, DU145 prostate, and MDA-MB-231 breast cancer) in a concentration- and time-dependent manner and induced G1 arrest of the cell cycle. It was also demonstrated that the selective cytotoxic effect of dichamanetin in cancer cells is mediated by the induction of oxidative stress. CONCLUSION: Our findings suggest that dichamanetin isolated from an edible herb has cancer chemotherapeutic potential.

In silico study of the ion channel formed by tolaasin I produced by Pseudomonas tolaasii.

A toxin produced by Pseudomonas tolaasii, tolaasin, causes brown blotch disease in mushrooms. Tolaasin forms pores on the cellular membrane and destroys cell structure. Inhibiting the ability of tolaasin to form ion channels may be an effective method to protect against attack by tolaasin. However, it is first necessary to elucidate the three-dimensional structure of the ion channels formed by tolaasin. In this study, the structure of the tolaasin ion channel was determined in silico based on data obtained from nuclear magnetic resonance experiments.

Deoxypodophyllotoxin induces G2/M cell cycle arrest and apoptosis in HeLa cells.

The natural flavolignan deoxypodophyllotoxin (DPPT) inhibits tubulin polymerization and induces cell cycle arrest at G(2)/M, followed by apoptosis. However, the precise mechanism of DPPT action is currently unknown. Here, we investigated the mechanism by which DPPT treatment of HeLa cervical carcinoma cells induces cell cycle arrest and apoptosis. We show that DPPT treatment inhibits cell viability in a dose-dependent manner and that this reduction in cell viability results from cell cycle arrest at G(2)/M phase, accompanied by an increase in apoptotic cell death. The induction of apoptosis by DPPT was confirmed by visualization of morphologic changes and internucleosomal DNA fragmentation. In addition, DPPT causes p53 and Bax to accumulate, accompanied by activation of DNA damage-sensing kinases, including ataxia-telangiectasia mutated (ATM) kinase and Chk2. Furthermore, DPPT activates caspase-3 and -7, suggesting that caspase-mediated pathways are involved in DPPT-induced apoptosis. Levels of the tumor suppressor PTEN were up-regulated during DPPT treatment, coincident with Akt inhibition. Together, these data suggest that DPPT induces G(2)/M cell-cycle arrest followed by apoptosis through multiple cellular processes, involving the activation of ATM, upregulation of p53 and Bax, activation of caspase-3 and -7, and accumulation of PTEN resulting in the inhibition of the Akt pathway.

A novel antiproliferative agent, phenylpyridineylbutenol, isolated from Streptomyces sp.

A novel compound showing antiproliferative effect was isolated from Streptomyces sp. Its structure was determined based on the interpretation of the NMR spectra, and its conformation was elucidated using molecular modeling and 2D NOESY. It was determined to be (E)-4-phenyl-3-(pyridine-2-yl)but-2-en-1-ol.